Self-healing Aqueous Batteries for Safe and Durable Green Transport

Description

Electric vehicle has been demonstrated as an effective way to reduce the environmental pollutions from the exhausts of conventional fuel-propelled transports, which is especially essential for the city of Hong Kong with many skyscrapers. Recently, the number of electric vehicles blooms in Hong Kong and globally, but it is also facing the increasing concerns on battery safety, lifetime, and recycling. Accidental and spontaneous car fires in electric vehicles mainly come from the flammable character of organic electrolytes used in the commercial batteries. The electrolytes are also toxic and corrosive to the environment. The short battery lifetime is mainly coursed by the morphology degradation of electrodes during cycling. As a result, less active storage sites decrease the battery capacity and more exposed surfaces induce side reactions for the poorer stability. Such conflict of high quantity demand on electric vehicles and short service time from performance fading also brings great pressure on the battery recycling requirements, due to the high costive elements and environmental unfriendly components used in the commercial batteries. In this project, we plan to develop high performance rechargeable batteries with non-flammable aqueous electrolytes and self-healing electrodes to tackle the aforesaid problems. The non-flammable aqueous electrolytes can effectively prevent the burning rick of electric vehicles. In this aspect, aqueous systems have significant advantages on ionic mobility, price, and availability over the nonflammable organic and solid-state alternatives. Considering electrode materials normally have higher solubility in water, which may worsen the electrode degradation, we will modify the electrode materials with the self-healing strategy to repair the crystal structures. Along with the enhanced battery lifetime, we will further select the associated aqueous electrolytes for the battery performance. The combination of the environmentally friendly system (aqueous) and prolonged lifetime (self-healing) can dramatically reduce the required battery recycling cost and quantity on the environment impact. Self-healing phenomena are common in nature, such as plant and human wounds. However, the reproduction is barely realized for polymers and metals in laboratory. Recently, the PC’s research group has demonstrated the possibility of self-healing strategy in the inorganic nonmetallic system and developed the preliminary aqueous prototypes. It is intended to further develop the self-healing strategy in various aqueous battery systems for the long lifetime of over 5000 cycles. Along with the investigation of suitable combination of the self-healing electrodes and aqueous electrolytes, a high energy density aqueous battery of 160 Wh/kg will be demonstrated. With the success of this project, we plan to combine all our previous research achievements on aqueous batteries and apply for the “HK Tech 300” innovation and entrepreneurship programme, organized by City University of Hong Kong, for the subsequent research and development of large-scale fabrication and fast-charging technology, and further collaborate with BTR New Material Group Co., Ltd. on the attractive products of self-healing electrodes for the global market share and NIO Inc. for their famous battery swap service of electric vehicles. The success of this project will develop safe and durable energy storage strategy for the green transport in Hong Kong and globally. Besides this urgent demand in electric vehicle society, the proposed self-healing aqueous battery technology can also benefit the broad applications of power storage, green construction industry and non-road mobile machinery (NRMM), considering the significant advantages on high safety and low cost. Moreover, the environmentally friendly and high-performance battery system can effectively contribute to the environmental protection and promote green transport for the Hong Kong’s climate action plan 2050.